:high voltage activated Ca2+ current NEURON { SUFFIX Hva USEION ca READ cai, cao WRITE ica RANGE ghvabar, ica, gca, eca } UNITS { (mA) = (milliamp) (mV) = (millivolt) } INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)} PARAMETER { v (mV) dt (ms) ghvabar= 0.00034 (mho/cm2) <0,1e9> } STATE { u z } ASSIGNED { ica (mA/cm2) uinf zinf utau (ms) ztau (ms) gca (mho/cm2) eca (mV) cai (mM) cao (mM) } INITIAL { rate(v) u = uinf z = zinf } BREAKPOINT { SOLVE states METHOD cnexp gca = ghvabar*u*u*z eca = 12.5 * log(cao/cai) ica = gca*(v-eca) } DERIVATIVE states { rate(v) u' = (uinf-u)/utau z' = (zinf-z)/ztau } UNITSOFF PROCEDURE rate(v (mV)) {LOCAL vu, vz, vx vx = -0.031*(v+37.1) vu = v+24.6 if (fabs(vu)<1e-04){ vu = vu+0.00001 uinf = 1/(1+exp(-(vu/11.3))) utau = (1.25*(2/(exp(vx) + exp(-vx)))) }else{ uinf = 1/(1+exp(-(vu)/11.3)) utau = (1.25*(2/(exp(vx) + exp(-vx)))) } vz = v+12.6 if (fabs(vz)<1e-04){ vz = vz+0.00001 zinf = 1/(1+exp(vz/18.9)) ztau = 420 }else{ zinf = 1/(1+exp(vz/18.9)) ztau = 420 } } UNITSON